Design of Poly(vinyldiaminotriazine)‐Based Nonviral Vectors via Specific Hydrogen Bonding with Nucleic Acid Base Pairs

Abstract

A novel gene transfer system that complexes plasmid DNA (pDNA) through complementary hydrogen bonding of guests with base pairs is reported. Poly(vinyldiaminotriazine) (PVDT) homopolymer and its copolymers with poly(1‐vinyl‐2‐pyrrolidone) are synthesized via conventional radical random polymerization, and water‐soluble fractions are collected. These PVDT‐based polymers efficiently complex pDNA and displace ethidium bromide (EB) in EB‐intercalated pDNA solutions because of the hydrogen‐bonding‐induced constrained state of pDNA. It is also found that upon complexation, pDNA seems to undergo B–C conformation change and circular dichroism spectra assumed a polymer‐and‐salt‐induced (psi)‐type pattern that is rationally ascribed to a certain change in the high‐order structure of DNA condensates. Transmission electron microscopy presented several morphologies of spheres and toroids within aggregates ≥ 100 nm, resembling DNA condensation induced by cationics. In transfection studies using pDNA‐encoding luciferase or enhanced green fluorescent protein, this system could efficiently transfect COS‐1 cells. Compared to the commercial polycation system, ExGen 500, these H‐bonding vectors display several merits such as higher transfection efficiency, lower cytotoxicity, better serum compatibility, and stability in the presence of bovine serum albumin (BSA). The results suggest that PVDT‐based polymers are superior to polycation counterparts with regard to their potential in vivo applications.

Effect of the Head-Group Geometry of Amino Acid-Based Cationic Surfactants on Interaction with Plasmid DNA

“…The reduction in the intensity of the 274 nm peak suggests a B-DNA to C-DNA transition; however, for this transition, the negative band should remain constant, which is not the case. The changes reported here have also been observed upon the interaction of DNA with cationic liposomes [66][67][68] and polycations 69 and have been attributed to "psi"-DNA condensation. 70 The values obtained from at least three experiments indicate that the minimum intensity at 274 nm obtained on the addition of the three surfactants occurs on charge ratios of 1.0 ( 0.1, 0.75 ( 0.1, and 0.65 ( 0.1 for Ala, Pro, and Phe, respectively.…”

“…The reduction in the intensity of the 274 nm peak suggests a B-DNA to C-DNA transition; however, for this transition, the negative band should remain constant, which is not the case. The changes reported here have also been observed upon the interaction of DNA with cationic liposomes – and polycations and have been attributed to “psi”-DNA condensation …”

High‐Strength Hydrogels with Integrated Functions of H‐bonding and Thermoresponsive Surface‐Mediated Reverse Transfection and Cell Detachment

“…Note that naked DNA and PVDT/DNA complex particles were respectively anchored on the surface for gene‐transfection evaluation in this study. The size and zeta potential of PVDT/DNA complex particles (PVDT/DNA weight ratio = 0.25) respectively measured as 1.3 µm and −4.2 mV, was reported in our previous work 25, 26. The adsorption efficiency of pDNA on the surface of hydrogels is enhanced with an increment of the content of VDT owing to the enrichment of more H‐bonding motifs on the surface (Supporting Information, Fig.…”

High-Strength Photoresponsive Hydrogels Enable Surface-Mediated Gene Delivery and Light-Induced Reversible Cell Adhesion/Detachment

“…For PAVSP1-0-0.05 without VDT, a very small number of fluorescent spots are observed in Figure S4a, indicating a small number of PVDT/pDNA nanocomplexes adsorbed via physical adsorption, which eventually results in a low transfection efficiency of 5.5 × 10 5 RLU/mg protein. As for PAVSP1-3-0.2 that exhibits maximal PVDT/pDNA adsorption, the highest transfection efficiency, 6.6 × 10 6 RLU/mg protein, is achieved; it is 11 times higher than that on PAVSP1-0-0.05 and much higher than that with the traditional liquid transfection method using PVDT as a vector as reported in our previous work . To examine the possible negative effect of UV light irradiation on pDNA, we measured the adsorption spectra of an aqueous solution of pDNA before and after UV irradiation by using a UV–vis spectrophotometer.…”